package demo.util;

import java.text.SimpleDateFormat;
import java.util.Date;

public class DateUtil {

    private static final long ONE_MINUTE = 60000L;
    private static final long ONE_HOUR = 3600000L;
    private static final long ONE_DAY = 86400000L;
    private static final long ONE_WEEK = 604800000L;

    private static final String ONE_SECOND_AGO = " 秒前";
    private static final String ONE_MINUTE_AGO = " 分钟前";
    private static final String ONE_HOUR_AGO = " 小时前";
    private static final String ONE_DAY_AGO = " 天前";
    private static final String ONE_MONTH_AGO = " 月前";
    private static final String ONE_YEAR_AGO = " 年前";

    private static final SimpleDateFormat yearFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
    private static final SimpleDateFormat yearFormatToMinute = new SimpleDateFormat("yyyy-MM-dd HH:mm");
    private static final SimpleDateFormat yearFormatToDay = new SimpleDateFormat("yyyy-MM-dd");
    private static final SimpleDateFormat monthFormat = new SimpleDateFormat("MM-dd HH:mm:ss");
    private static final SimpleDateFormat monthFormatToMinute = new SimpleDateFormat("MM-dd HH:mm");
    private static final SimpleDateFormat monthFormatToDay = new SimpleDateFormat("MM-dd");
    private static final SimpleDateFormat timeFormat = new SimpleDateFormat("HH:mm:ss");

    // 实际调用方法
    public String timeCount(Date dateTime) {
        return format(dateTime);
    }

    // 时间转换
    public static String format(Date date) {
        long delta = new Date().getTime() - date.getTime();
        if (delta < 1L * ONE_MINUTE) {
            long seconds = toSeconds(delta);
            return (seconds <= 0 ? 1 : seconds) + ONE_SECOND_AGO;
        }
        if (delta < 45L * ONE_MINUTE) {
            long minutes = toMinutes(delta);
            return (minutes <= 0 ? 1 : minutes) + ONE_MINUTE_AGO;
        }
        if (delta < 24L * ONE_HOUR) {
            long hours = toHours(delta);
            return (hours <= 0 ? 1 : hours) + ONE_HOUR_AGO;
        }
        if (delta < 48L * ONE_HOUR) {
            return "昨天 " + timeFormat.format(date);
        }
        Date dateNow = new Date();
        if (date.getYear() != dateNow.getYear()) {
            return yearFormat.format(date);
        }
        return monthFormat.format(date);

//        if (delta < 30L * ONE_DAY) {
//            long days = toDays(delta);
//            return (days <= 0 ? 1 : days) + ONE_DAY_AGO;
//        }
//        if (delta < 12L * 4L * ONE_WEEK) {
//            long months = toMonths(delta);
//            return (months <= 0 ? 1 : months) + ONE_MONTH_AGO;
//        } else {
//            long years = toYears(delta);
//            return (years <= 0 ? 1 : years) + ONE_YEAR_AGO;
//        }
    }

    public static String formatToDay(Date date) {
        if (date == null) {
            return "";
        }

        Date dateNow = new Date();

        if (date.getYear() != dateNow.getYear()) {
            return yearFormatToDay.format(date);
        }
        return monthFormatToDay.format(date);
    }

    public static String formatToMinute(Date date) {
        if (date == null) {
            return "";
        }

        Date dateNow = new Date();

        if (date.getYear() != dateNow.getYear()) {
            return yearFormatToMinute.format(date);
        }
        return monthFormatToMinute.format(date);
    }

    private static long toSeconds(long date) {
        return date / 1000L;
    }

    private static long toMinutes(long date) {
        return toSeconds(date) / 60L;
    }

    private static long toHours(long date) {
        return toMinutes(date) / 60L;
    }

    private static long toDays(long date) {
        return toHours(date) / 24L;
    }

    private static long toMonths(long date) {
        return toDays(date) / 30L;
    }

    private static long toYears(long date) {
        return toMonths(date) / 365L;
    }
}
